Sheet holding tool



June 6, 1944. A. A. M-ELCHER 2,350,630

v SHEET HOLDING TOOL Filed Aug. 4, 1942 x r I Patented June 6, 1944 2,350,630 SHEET HOLDING TOOL Alfred A. Melcher, Los Angeles, Califl, assi'gnor of one-half to Francis L. Smith, Los Angeles,

C lif.

Application August 4, 1942, Serial No. 453,534

4. Claims.

My invention relates to a tool for temporarily holding, in proper relative positions, sheets of metal which are to be secured to, each otherv by rivets or the like, for instance, the sheets, or thin plates of metal that form the skin or outer sheathing of airplane bodies, each of which plates, it will be understood, is formed with a large number of rivet holes, which, when the plates are assembled for permanent'connection. must register with similar rivetholesformed in another plate in order to save time, labor and consequent expense in the fabrication of the airplane or other structure of which the plates form a part.

The principal object of my invention is, to provide a simple, inexpensive and practical tool, capable of being conveniently used for'rapidlyeffecting a temporary connection or tie between structural plates or sheets, so as to bring about registration of the corresponding rivet holes therein, thus enabling the rivets to be quickly positioned and set in the registering holes and which tool, after having served'its purpose, is capable of being readily removed from the hole in which it. has been positioned;

A further object of my invention is toprovide a tool of the character referred to, which includes a collet having a radially expansible head which, when in contracted condition is capable of being inserted through registering rivet holes in two plates or sheets which are to be permanently connected, and after such insertion, said head is expanded radially so as to secure the collet in the registering rivet holes, thus insuring and maintaining registration of the corresponding holes in a the sheets or plates and greatly expediting the work incident to riveting operationsf With the foregoing and other objectsin view, my invention consists in certain novel features of construction and arrangement of 'parts which will I be hereinafter more fully described and claimed and illustrated in the accompanying drawing,'in which:

Fig. 1 is a longitudinal section taken through the center of a sheet or plate holder constructed in accordance with my invention, and showing the collapsed head of the collet in position, passing through registering rivet holesQ Fig. 2 is a sectional view similar to Fig. 1 with the collet head in expanded condition after its passage through the registering rivet holes.

Fig. 3 is a perspective view of the collet.

Fi 4 is a detail section taken on theline 4 -4 of Fig. 1.

Fig. 5 is an enlarged horizontal section taken on the line 5-501 Fig. 3. f

Fig. 6 is an enlarged horizontal section taken onthe line 6-5 of Fig. 2'. l Referring by numerals to the accompanying drawing which illustrates a preferred embodie ment of my invention, It] designatesthe body of my improved tool which is substantially cylindrical in form and providedwith an axial chamber ll of uniform diameter throughout its length. The forward end of this body is rounded as designated by I2 and provided with a finished surfaceso as not to scratch, or mar the surfaces of the plates on which the tool is used. IA flange l3 projects inwardly from the forward end of" the Wall of body It], thereby providing a centrally ar ranged opening l4. t

Formed on the lower portion of body Ill-'isan external shoulder l5 that is adaptedlto be en gaged by the jaw J of a pair of specially formed pliers utilized in manipulating thetool when the same is applied to and removed from the'shee'ts and which pliers include a plunger 1? which co operates with said jaw, Arranged to slide freely in the lower 'portion'of the tubular body I0 is a substantially cylindrical block or plunger l6 provided with an axiallydisposed chamber l1, and the upperportion o'fsaid block is provided with a longitudinallydisposed diametrical slot l8 which intersects chamberll. The upper end of the chamber I1 is reduced in diameter toform shoulders l9 on those portions of the walls to, the sides of slot, l8), and formed in said walls above the central portionsof said shoulders are notches 20.v v Arranged for sliding movement within the chamber I0 and through the opening I4 in the forward end of the body is a collet comprising a ,tubular body 2| provided on its lower end'with an external flange 22 which durlng' relative movement between the collet andbjody It] bears against the inner surfaces of the wall surrounding chamber II.

The upper portion of the body of ,the collet is reduced in diameter as to form a short cylindrical portion 23, the outer end of which terminates in a substantially spherical head. This head and cylindrical portion 23 are providedwith longitudinally disposed slots 24, there being provided two slots disposed ninety degrees apart, thus forming between said slotsand heads. four identical fingers 25,, the outer ends of. which .iter; minate in head 'segments 26.

The bore through the tubular'collet, terminates at a point just below the headsegments2 6 ,therer by providing internally arranged inclined shoulders 21.

The slots 24 are formed in the reduced forward portion 23 of the collet While said reduced portion .is in cylindrical form and after the formation of said ends, the collet is heat treated, so as to develop internal stresses which cause the outer portions of the fingers 25 and the head segments, to normally collapse or move toward each other, and to resist expansive movement. Thus the collet when finished, has the appearance as illustrated in Fig. 3, with the reduced portion 24 gradually tapering from the body 2| to the head segments 25 and with the side faces of the latter in direct contact with each other. The diameter of the collapsed heads is such that it will readily pass through the rivet holes in the plates on which the tool is used.

Surrounding the body 2| of the collet and interposed between the flange 3 and the flange 22 is an expansive spring 28 which normally tends to move the body l and'collet in opposite directions. Seated in the lower portion of body III are the ends of a diametrically disposed pin 2: which passes through the slots H3 in plunger l i r Surrounding the central portion of this pin is a loop 30 "which is formed on the lower end of a rod 3|, the same extending into the bore through the body of the collet and between the fingers 25.

This rod extends through the notches 2|] that are formed in the shoulders l9 at the upper end of chamber l1, and said shoulders l9 provide a stop which is engaged by the loop 30 to limit the outward movement of the plunger l6 relative to the body.

It is to be noted that all of the parts of the holder are maintained in assembled relation by pin: 29, and such construction provides a highly desirable safety feature, and even though the fingers and'head segments 26 are broken off, the parts of the device can not fly apart under the expansive forces of spring 28, and consequently eliminating possibility of injury to workmen. r r Under normal conditions or before the expanded head is inserted through registering rivet holes in a pairof plates or the like, body U and plunger [8 are forced in opposite directions under the influence of spring 28, and under such conditions, the shoulders l9 at the upper end of plunger l6 bear against theupper portion of loop with the expansible head. comprising the segments 26 occupying a position just beyond the rounded end l2 of body l0, and with the end of rod 3| between the segments so that the same are expanded.- I 1 To insert the expansible head of the tool through registering rivet holes to tie a pair of plates together .and bring .into registration the corresponding rivet holes so asrto facilitate riveting operations, the jaw J of the pliers used for manipulating the tool is positioned against shoulder l5 and with the plunger Pof said pliers bearing against theend of cylindrical block l6, as illustrated bydotted lines in Fig. 1.

The pliers are now manipulated so as to move theplunger and jaw thereof toward each other, andthus .the body l0 and block l6 are correspondingly moved so as to compress spring 28 and move block 16 and collet 2| forwardly through body "I, consequently, movingthe expansible head away from the forward-end, of body l0 until the shoulders 21 within the exter (is attached to the rear portion of body Ill by pin 29.

As the expansible head passes beyond the end of rod 3|, the resiliency in the fingers 24 will collapse the head by drawing the segments thereof radially toward each other, thus materially decreasing the diameter of the head and enablin thesame to be passed through the registering rivet holes as illustrated in Fig. 1.

After the expansible head has thus been passed through the rivet holes, the pressure of the parts of the plier on the tool are relieved whereupon spring 28 acts to move the collet and plunger l6 .rearwardly through body l0 and after the shoulders 21 ridepast the end of rod 3|, the head comprising the segments 26 expands radially beyond the connected plates and at the end of this movement, the plates or sheets are tied to each other by those portions of the resilient fingers immediately adjacent theexpansible head, as illustrated in Fig. 2, with the end of body l0 bearing against the outer face of one sheet or plate, and the expanded head bearing against the outer face of the other sheet.

Thus, the plates or sheets are securely tied to each other in proper assembled relation and with the corresponding rivet holes in registration so as to facilitate the positioning and setting of the rivets. v v

To remove the tool from the work after riveting operations, the pliers are brought into use so as to move body I0 and plunger l6 toward each other a suflicient distance to Withdraw the end of rod 3| from between the head segments which permits the latter to contract by radial movement toward each other, thus decreasing the diameter of the head to such a degree as to enable the same to be withdrawn through the rivet holes in which the tool has been positioned. An especially desirable feature of my invention is the collet provided with the normally contract- Ted fingers 25 and head segments 26 which are radially expansible and which structure results in a substantial increase in the size of the head at the outer end of the collet when the same is expanded, such radial expansion being a decided improvement over the spreading or wedging action of a collet which is split so as to provide only 7 two fingers and heads.

pansible head pass the end of rod 3|, which lat- Thus, it will be seen that I'have provided a sheet holding-tool that is relatively simple in construction, inexpensive of manufacture, and very effective in performing the functions for which it is intended; namely, the temporary connecting or holding of sheets or plates that are to be permanently fastened to each other by means of rivets, or the like.

It will be understood that minor changes in the size, form and construction of the various parts of my improved sheet holding tool may be made and substituted for those herein shown and described without departing from the spirit of my invention, the scope of which is set forth in the appended claims.

Iclaim as my invention:

1. In a sheet holding tool, a pair of telescopically associated members, the inner one of which has a normally contracted radially expansible portion which projects from the other member, said expansible portion being provided near its outer end with a shoulder, a plunger arranged for sliding movement in the rear portion of the outer one of said telescopic members and bearing against the rear 'end of the inner one of said members, an expansive coil spring arranged between said telescopic members, a rod extending lengthwise through the inner one of said telescopic members, the end of which rod is adapted to engage the shoulder on the expansible portion of said inner member, and means connecting the rear end of said rod with the outer one of said telescopic members, which connecting means and the rear end of said rod have sliding engagement with said plunger.

- said expansible portion being provided near its outer end with an internal shoulder, an expansive spring between said telescopic members, a plunger arranged for sliding movement in the rear portion of the outer one of said telescopic members which plunger is slotted longitudinally, a pin seated in the rear portion of the outer telescopic member, which pin passes through the slot in said plunger, a rod arranged to slide through the inner one of said telescopic members and connected to said pin and a loop formed on the rear end of said rod for the reception of said pm.

4. A sheet holding tool as set forth in claim 3 and with a shoulder within said plunger for limiting the movement of said rod in one direction.

ALFRED A. MELCHER. 

